tpm: fix byte order related arithmetic inconsistency in tpm_getcap()
You should not do arithmetic with __be32 or __le32 types because
sometimes it results incorrect results. Calculations must be done only
with integers that are in in the CPU byte order. This commit migrates
tpm_getcap() to struct tpm_buf in order to sort out these issues.
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 4ed08ab..be54159 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -552,31 +552,33 @@ static const struct tpm_input_header tpm_getcap_header = {
ssize_t tpm_getcap(struct tpm_chip *chip, u32 subcap_id, cap_t *cap,
const char *desc, size_t min_cap_length)
{
- struct tpm_cmd_t tpm_cmd;
+ struct tpm_buf buf;
int rc;
- tpm_cmd.header.in = tpm_getcap_header;
+ rc = tpm_buf_init(&buf, TPM_TAG_RQU_COMMAND, TPM_ORD_GET_CAP);
+ if (rc)
+ return rc;
+
if (subcap_id == TPM_CAP_VERSION_1_1 ||
subcap_id == TPM_CAP_VERSION_1_2) {
- tpm_cmd.params.getcap_in.cap = cpu_to_be32(subcap_id);
- /*subcap field not necessary */
- tpm_cmd.params.getcap_in.subcap_size = cpu_to_be32(0);
- tpm_cmd.header.in.length -= cpu_to_be32(sizeof(__be32));
+ tpm_buf_append_u32(&buf, subcap_id);
+ tpm_buf_append_u32(&buf, 0);
} else {
if (subcap_id == TPM_CAP_FLAG_PERM ||
subcap_id == TPM_CAP_FLAG_VOL)
- tpm_cmd.params.getcap_in.cap =
- cpu_to_be32(TPM_CAP_FLAG);
+ tpm_buf_append_u32(&buf, TPM_CAP_FLAG);
else
- tpm_cmd.params.getcap_in.cap =
- cpu_to_be32(TPM_CAP_PROP);
- tpm_cmd.params.getcap_in.subcap_size = cpu_to_be32(4);
- tpm_cmd.params.getcap_in.subcap = cpu_to_be32(subcap_id);
+ tpm_buf_append_u32(&buf, TPM_CAP_PROP);
+
+ tpm_buf_append_u32(&buf, 4);
+ tpm_buf_append_u32(&buf, subcap_id);
}
- rc = tpm_transmit_cmd(chip, NULL, &tpm_cmd, TPM_INTERNAL_RESULT_SIZE,
+ rc = tpm_transmit_cmd(chip, NULL, buf.data, PAGE_SIZE,
min_cap_length, 0, desc);
if (!rc)
- *cap = tpm_cmd.params.getcap_out.cap;
+ *cap = *(cap_t *)&buf.data[TPM_HEADER_SIZE + 4];
+
+ tpm_buf_destroy(&buf);
return rc;
}
EXPORT_SYMBOL_GPL(tpm_getcap);